*Michelle Williams is cracking up over rumors that she has undergone surgery for butt implants, insisting her backside is all “natural.”

The “Destiny’s Child singer was said to be toting around more badonkadonk on the red carpet at Sunday’s Tony Awards, prompting the gossip site Media Take Out to suggest she had gone under the knife.

But Williams is amused by the claims and credits a new exercise regime, as well as her love of soul food, with her bigger booty.

Taking to her Twitter page, she writes, “I’m proud of my natural assets!!! Do some lunges and you can have one too!!! Thanks!!! LOL (laugh out loud)!!!

“I also wanna thank my momma!!! I wanna thank my granny for feeding me great northern beans and cornbread too!!!”